Apparatus for the pretreatment and subsequent conveying, plastification, or agglomeration of plastics

ABSTRACT

Disclosed is an apparatus for the processing of plastics, having a container with a rotatable mixing implement, where a conveyor is provided, with a screw rotating in a housing, wherein the imaginary continuation of the longitudinal axis of the conveyor in a direction opposite to the direction of conveying passes the axis of rotation, where, on the outflow side, there is an offset distance between the longitudinal axis and the radial that is parallel to the longitudinal axis, wherein on the internal wall area of the container, there is at least one bar-shaped deflector which is directed into the interior of the container, and the height profile of which decreases in the direction of rotation of the mixing implement, seen from above, and the angle included thereby, over its length, with a plane (E) perpendicular to the axis of rotation of the mixing implements is an acute angle (α).

This application is a U.S. National Phase of International ApplicationNo. PCT/AT2012/050156, filed Oct. 12, 2012, which claims priority toAustrian Patent Application No. A 1511/2011, filed Oct. 14, 2011, thedisclosures of which are incorporated by reference herein.

BACKGROUND

The invention relates to an apparatus for the pretreatment andsubsequent conveying, plastification, or agglomeration of plastics.

The prior art reveals numerous similar apparatuses of varying design,comprising a receiver (receiving container) or cutter compactor for thecomminution, heating, softening and treatment of a plastics material tobe recycled, and also, attached thereto, a conveyor or extruder for themelting of the material thus prepared. The aim here is to obtain a finalproduct of the highest possible quality, mostly in the form of pellets.

By way of example, EP 123 771 or EP 303 929 describe apparatuses with areceiver and, attached thereto, an extruder, where the plastics materialintroduced into the receiver is comminuted through rotation of thecomminution and mixing implements and is fluidized, and issimultaneously heated by the energy introduced. A mixture withsufficiently good thermal homogeneity is thus formed. This mixture isdischarged after an appropriate residence time from the receiver intothe screw-based extruder, and is conveyed and, during this process,plastified or melted. The arrangement here has the screw-based extruderapproximately at the level of the comminution implements. The softenedplastics particles are thus actively forced or stuffed into the extruderby the mixing implements.

Most of these designs, which have been known for a long time, areunsatisfactory in respect of the quality of the treated plasticsmaterial obtained at the outgoing end of the screw, and/or in respect ofthe quantitative output of the screw. Studies have shown that therequirements placed upon the screw downstream of the container, mostly aplastifying screw, differ during the course of the operation, and thatthis is attributable to container residence times that are longer forsome batches of the product to be processed than for other batches. Theaverage residence time of the material in the container is calculated bydividing the weight of the charge in the container by the amountdischarged from the screw per unit of time. However, this averageresidence time is—as mentioned—generally not valid for large portions ofthe material to be processed, but instead there are irregularsubstantial upward and downward deviations from this average value.These deviations may be attributable to differences in the nature of thebatches of product introduced successively into the container, e.g.differences in the nature or thickness of the plastics material, e.g.foil residues, etc., or else uncontrollable events.

For material that is thermally and mechanically homogeneous, there isusually a quality improvement in the product obtained at the outgoingend of the screw when the flight depth of the metering zone of the screwis very large and the screw rotation rate is kept very small. However,if it is desirable to increase the quantitative output of the screw orto improve the performance for example of a shredder-extrudercombination, the screw rotation rate must then be raised, and this meansthat the shear level is also raised. However, this causes the screw tosubject the processed material to higher mechanical and thermal stress,and there is therefore the risk of damage to the molecular chains of theplastics material. Another disadvantage that can arise is greater wearof the screw and of its housing, in particular during the processing ofrecycling material, by virtue of the contaminants present in thismaterial, e.g. abrasive particles, metal parts, etc., which cause severewear of the metal parts as they slide across one another, in the screwor in its bearings.

However, an effect that occurs both with slow-running and deep-cutscrews (large flight depth) and with fast-running screws is that, aspreviously mentioned, differences in quality of individual batches ofmaterial introduced to the screw, e.g. differences in flake size and/ordifferences in temperature of the plastics material, have adisadvantageous effect with regard to inhomogeneity of the plasticsmaterial obtained at the outgoing end of the screw. In order tocompensate for this inhomogeneity, the temperature profile of theextruder is in practice raised, and this means that additional energyhas to be introduced into the plastic, thus subjecting the plasticsmaterial to the thermal damage mentioned and increasing the amount ofenergy required. Another result here is that the viscosity of theplastics material obtained at the outgoing end of the extruder isreduced, and this makes the material more free-flowing, with concomitantdifficulties in the further processing of this material.

It can be seen from this that the process parameters that areadvantageous for obtaining material of good quality at the outgoing endof the screw are mutually contradictory.

In an initial attempt to solve this problem, the diameter of the cuttercompactor was increased in relation to the diameter of the screw. Thisenlargement of the container in comparison with conventional sizesimproved the mechanical and thermal homogeneity of the plastics materialpretreated in the container. The reason for this was that the ratio bymass of the continuously added untreated “cold” portions of material tothe amount of material present in the container and already to someextent treated was smaller than under the conditions that usuallyprevail, and that the average residence time of the plastics material inthe container was substantially increased. This reduction of the ratioby mass had an advantageous effect on the thermal and mechanicalhomogeneity of the material entering the screw housing from thecontainer, and with this had a direct advantageous effect on the qualityof the plastified or agglomerated material at the end of the extruderscrew or of the agglomerating screw, since the product initiallyintroduced to the screw was at least approximately of identicalmechanical and thermal homogeneity, and therefore the screw itself wasnot required to achieve this homogeneity. The theoretical residence timeof the treated plastics material in the container was approximatelyconstant. Furthermore, this type of system with enlarged container wasless sensitive than the known systems in relation to the accuracy ofinput portions.

Systems of this type were therefore in principle capable of effectiveuse, and advantageous. However, although systems using containers orcutter compactors with large diameters, e.g. of 1500 mm or more, andwith relatively long residence times, have good functionality, andalthough the quality of the recylate is high, they are not ideal interms of space required and of efficiency, or they emit a large amountof heat.

Another feature shared by these known apparatuses is that the directionof conveying or of rotation of the mixing and comminution implements,and therefore the direction in which the particles of material circulatein the receiver, and the direction of conveying of the conveyor, inparticular of an extruder, are in essence identical or have the samesense. This arrangement, selected intentionally, was the result of thedesire to maximize stuffing of the material into the screw, or toforce-feed the screw. This concept of stuffing the particles into theconveying screw or extruder screw in the direction of conveying of thescrew was also very obvious and was in line with the familiar thinkingof the person skilled in the art, since it means that the particles donot have to reverse their direction of movement and there is thereforeno need to exert any additional force for the change of direction. Anobjective here, and in further derivative developments, was always tomaximize screw fill and to amplify this stuffing effect. By way ofexample, attempts have also been made to extend the intake region of theextruder in the manner of a cone or to curve the comminution implementsin the shape of a sickle, so that these can act like a trowel in feedingthe softened material into the screw. Displacement of the extruder, onthe inflow side, from a radial position to a tangential position inrelation to the container further amplified the stuffing effect, andincreased the force with which the plastics material from thecirculating implement was conveyed or forced into the extruder.

Apparatuses of this type are in principle capable of functioning, andthey operate satisfactorily, although with recurring problems:

By way of example, an effect repeatedly observed with materials with lowenergy content, e.g. PET fibres or PET foils, or with materials which ata low temperature become sticky or soft, e.g. polylactic acid (PLA) isthat when, intentionally, stuffing of the plastics material into theintake region of the extruder or conveyor, under pressure, is achievedby components moving in the same sense, this leads to premature meltingof the material immediately after, or else in, the intake region of theextruder or of the screw. This firstly reduces the conveying effect ofthe screw, and secondly there can also be some reverse flow of this meltinto the region of the cutter compactor or receiver, with the resultthat flakes that have not yet melted adhere to the melt, and in turn themelt thus cools and to some extent solidifies, with resultant formationof a clump or conglomerate made of to some extent solidified melt and ofsolid plastics particles. This causes blockage on the intake and cakingof the mixing and comminution implements. A further consequence isreduction of the throughput or quantitative output of the conveyor orextruder, since adequate filling of the screw is no longer achieved.Another possibility here is that movement of the mixing and comminutionimplements is prevented. In such cases, the system normally has to beshut down and thoroughly cleaned.

Problems also occur with polymer materials which have already beenheated in the cutter compactor up to the vicinity of their meltingrange. If overfilling of the intake region occurs here, the materialmelts and intake is impaired.

Problems are also encountered with fibrous materials that are mostlyorientated and linear, with a certain amount of longitudinal elongationand low thickness or stiffness, for example plastics foils cut intostrips. A main reason for this is that the elongate material is retainedat the outflow end of the intake aperture of the screw, where one end ofthe strip protrudes into the receiver and the other end protrudes intothe intake region. Since the mixing implements and the screw are movingin the same sense or exert the same conveying-direction component andpressure component on the material, both ends of the strip are subjectedto tension and pressure in the same direction, and release of the stripbecomes impossible. This in turn leads to accumulation of the materialin the said region, to a narrowing of the cross section of the intakeaperture, and to poorer intake performance and, as a furtherconsequence, to reduced throughput. The increased feed pressure in thisregion can moreover cause melting, and this in turn causes the problemsmentioned in the introduction. Another problem is efficient andnon-aggressive introduction of the material into the screw whileavoiding blockages, and achieving greater intensity of treatment of thematerial in the container.

SUMMARY

It is therefore an object of the present invention to overcome thedisadvantages mentioned and to improve an apparatus of the typedescribed in the introduction in such a way as to permit problem-freeintake of materials by the screw, even of those that are sensitive orstrip-shaped, and to permit processing or treatment of these materialsto give material of high quality, with high throughput, while makingefficient use of time, saving energy, and minimizing space requirement.

The characterizing features of certain embodiments achieve this objectin an apparatus of the type mentioned in the introduction.

A first provision here is that the imaginary continuation of the centrallongitudinal axis of the conveyor, in particular extruder, if this hasonly a single screw, or the longitudinal axis of the screw closest tothe intake aperture, if the conveyor has more than one screw, in adirection opposite to the direction of conveying of the conveyor,passes, and does not intersect, the axis of rotation, where, on theoutflow side, there is an offset distance between the longitudinal axisof the conveyor, if this has a single screw, or the longitudinal axis ofthe screw closest to the intake aperture, and the radial that isassociated with the container and that is parallel to the longitudinalaxis and that proceeds outwards from the axis of rotation of the mixingand/or comminution implement in the direction of conveying of theconveyor.

The direction of conveying of the mixing implements and the direction ofconveying of the conveyor are therefore no longer in the same sense, asis known from the prior art, but instead are at least to a small extentin the opposite sense, and the stuffing effect mentioned in theintroduction is thus reduced. The intentional reversal of the directionof rotation of the mixing and comminution implements in comparison withapparatuses known hitherto reduces the feed pressure on the intakeregion, and the risk of overfilling decreases. In this way, excessmaterial is not stuffed or trowelled with excess pressure into theintake region of the conveyor, but instead, in contrast, there is infact in turn a tendency to remove excess material from that region, insuch a way that although there is always sufficient material present inthe intake region, the additional pressure exerted is small or almostzero. This method can provide adequate filling of the screw and constantintake of sufficient material by the screw, without any overfilling ofthe screw with, as a further consequence, local pressure peaks where thematerial could melt.

Melting of the material in the region of the intake is thus prevented,and operating efficiency is therefore increased, maintenance intervalsare therefore lengthened, and downtime due to possible repairs andcleaning measures is reduced.

By virtue of the reduced feed pressure, displaceable elements which canbe used in a known manner to regulate the degree of filling of the screwreact markedly more sensitively, and the degree of filling of the screwcan be adjusted with even greater precision. This makes it easier tofind the ideal point at which to operate the system, in particular forrelatively heavy materials, for example regrind made of high-densitypolyethylene (HDPE) or PET.

Surprisingly and advantageously it has moreover been found thatoperation in the opposite sense, according to the invention, improvesintake of materials which have already been softened almost to the pointof melting. In particular when the material is already in a doughy orsoftened condition, the screw cuts the material from the doughy ringadjacent to the container wall. In the case of a direction of rotationin the direction of conveying of the screw, this ring would instead bepushed onward, and removal of an outer layer by the screw would not bepossible, with resultant impairment of intake. The reversal of thedirection of rotation, according to the invention, avoids this.

Furthermore, the retention or accumulation phenomena formed in the caseof the treatment of the above-described strip-shaped or fibrousmaterials can be resolved more easily, or do not occur at all, since, atthe aperture edge situated in the direction of rotation of the mixingimplements on the outflow side or downstream, the direction vector forthe mixing implements and the direction vector for the conveyor point inalmost opposite directions, or in directions that at least to a smallextent have opposite sense, and an elongate strip cannot thereforebecome curved around, and retained by, the said edge, but insteadbecomes entrained again by the mixing vortex in the receiver.

A factor that assists this behaviour of the apparatus is that, on theinternal wall area of the container, there is at least one bar-shapeddeflector which is directed into the interior of the container, and theheight profile of which decreases in the direction of rotation of themixing implement, seen from above, and the angle included thereby, overits length, with a plane perpendicular to the axis of rotation of themixing implements is an acute angle.

The overall effect of the design according to the invention is thatintake performance is improved and throughput is markedly increased. Thestability and performance of the entire system made of cutter compactorand conveyor is thus increased.

The effect of this specific design of a cutter-compactor/conveyor systemis that—contrary to previous expectations—it is also possible to usecontainers or cutter compactors with relatively small diameters, andthat it is possible to achieve high throughput performance levels andhigh quantitative output even with low residence time.

Because of the opposite direction of rotation of the mixing implements,the intake behaviour of the screw is not aggressive, and it is thereforepossible, in the cutter compactor, to use implements that are moreaggressive and that introduce more energy into the material. This alsoreduces the average residence time of the material in the cuttercompactor. Accordingly, the cutter compactor can be operated atrelatively high temperature, a consequence of which is in turn betterhomogeneity. Containers with relatively small diameters and residencetimes can therefore also be used successfully to prepare the material.

Another unexpected consequence of this type of combination of cuttercompactor and extruder is improved introduction and melting performanceof the material in an attached extruder. This provides compensation forpossible inhomogeneity, and the material that passes from the containerinto the screw housing and is then compressed and melted has highthermal and mechanical homogeneity. The final quality of the plastifiedor agglomerated material at the end of the extruder screw or of theagglomerating screw is correspondingly also very high, and it ispossible to use screws which, because of the pretreatment and theintake, treat the polymer in a non-aggressive manner and introduce aparticularly small amount of shear into the material in order to meltthe same. The extent of possible blockages of the intake aperture isreduced. Irrespective of the direction of rotation of the screw, theintroduction of material into the screw of assisted, and the performanceof the implements in the stuffing and introduction procedure isimproved.

So as to be able to achieve adaptation appropriate for various materialsand fill volumes, it is possible according to the invention that theangle is constant at least in sections over the length of the deflector,or that the profile of the deflector is curved, in particular curveddownwards, at least over a section of its length, and in that case theangle represents the tangential angle present at the respective point onthe deflector, and/or that the angle in particular in the central regionof the deflector, is from 15° to 45°, preferably from 20° to 40°, and/orthat the angle decreases towards the lower end of the deflector,optionally to an angle α=0°.

To assist the intake performance of the screw and the introduction ofmaterial into the intake aperture, it has proved advantageous if thelower end of the deflector is within a circumferential region of thecontainer between the two lateral edges of the intake aperture, and thisregion is optionally enlarged in the direction of rotation of theimplements by at most from 50% to 80% of the length of a longitudinaledge, and/or if the lower end of the deflector is at a height level onthe container wall, where this level is within the region between theupper and lower longitudinal edge of the intake aperture and optionallyat most from 50% to 80% of the height of the intake aperture above theupper longitudinal edge or at most from 20% to 30% of the height of theintake aperture below the lower edge of the intake aperture, and/or ifthe upper end of the deflector, viewed in the direction of rotation ofthe mixing implements, is at least 10° to 15°, preferably 30° to 55°,prior to that edge that is associated with the intake aperture and thatis situated upstream in the direction of rotation, or after that edgethat is associated with the intake aperture and that is situateddownstream in the direction of rotation.

It is possible that the bar-shaped deflector has a rectangular crosssection optionally rounded at the edges projecting into the container,and is secured by its narrow side on the internal wall of the container.Deflectors having rectangular cross section are especially attached onthe internal wall of the container in a manner such that they protruderadially from the internal wall of the container.

The width and length of the stripping elements can be adapted to beappropriate to the nature of the materials and treatment thereof, andthe desired introduction behaviour. It is also possible that the widthof the deflector increases in the direction towards the end or,optionally in stages, decreases.

It is advantageous if the width of the deflector is in the range from 1%to 10% of the diameter of the container.

In the case of a specific formation of a deflector, it is possible thatthe lower end representing the lowest section of the deflector isfollowed by an extension, which is directed upwards in the direction ofrotation, in particular as a single piece. It is thus possible inparticular to improve the flow of material downstream of the intakeaperture in the direction of rotation.

It has been found to be beneficial for intake performance if thedeflector ends outside of the open cross section of the intake aperture.

Other advantageous embodiments of the invention are described via thefollowing features:

Operation of the apparatus is particularly advantageous when theconstant K is in the range from 90 to 170. At these K values, or at thecontainer sizes and residence times associated therewith, the implementtransfers the material particularly effectively to the conveyor, andthere is a particularly good balance between the other features that areto some extent negatively correlated: the container size, the residencetime, the intake behaviour or the throughput, and the quality of thefinal product.

According to one advantageous development of the invention, it isenvisaged that the conveyor is arranged on the receiver in such a waythat the scalar product of the direction vector (direction vector thatis associated with the direction of rotation) that is tangential to thecircle described by the radially outermost point of the mixing and/orcomminution implement or to the plastics material transported past theaperture and that is normal to a radial of the receiver, and that pointsin the direction of rotation or of movement of the mixing and/orcomminution implement and of the direction vector that is associatedwith the direction of conveying of the conveyor at each individual pointor in the entire region of the aperture or at each individual point orin the entire region immediately radially prior to the aperture is zeroor negative. The region immediately radially prior to the aperture isdefined as that region which is prior to the aperture and at which thematerial is just about to pass through the aperture but has not yetpassed the aperture. The advantages mentioned in the introduction arethus achieved, and there is effective avoidance of all types ofagglomeration in the region of the intake aperture, brought about bystuffing effects. In particular here, there is also no dependency on thespatial arrangement of the mixing implements and of the screw inrelation to one another, and by way of example the orientation of theaxis of rotation does not have to be normal to the basal surface or tothe longitudinal axis of the conveyor or of the screw. The directionvector that is associated with the direction of rotation and thedirection vector that is associated with the direction of conveying liewithin a, preferably horizontal, plane, or in a plane orientated so asto be normal to the axis of rotation.

In another advantageous embodiment, the angle included between thedirection vector that is associated with the direction of rotation ofthe mixing and/or comminution implement and the direction vector that isassociated with the direction of conveying of the conveyor is greaterthan or equal to 90° and smaller than or equal to 180°, where the angleis measured at the point of intersection of the two direction vectors atthe edge that is associated with the aperture and that is situatedupstream in relation to the direction of rotation or of movement, inparticular at the point that is on the said edge or on the aperture andis situated furthest upstream. This therefore describes the range ofangles within which the conveyor must be arranged on the receiver inorder to achieve the advantageous effects. In the entire region of theaperture or at each individual point of the aperture, the forces actingon the material are therefore orientated at least to a small extent inan opposite sense, or in the extreme case the orientation isperpendicular and pressure-neutral. At no point of the aperture is thescalar product of the direction vectors of the mixing implements and ofthe screw positive, and no excessive stuffing effect occurs even in asubregion of the aperture.

Another advantageous embodiment of the invention provides that the angleincluded between the direction vector that is associated with thedirection of rotation or of movement and the direction vector that isassociated with the direction of conveying is from 170° to 180°,measured at the point of intersection of the two direction vectors inthe middle of the aperture. This type of arrangement is relevant by wayof example when the conveyor is arranged tangentially on the cuttercompactor.

In order to ensure that no excessive stuffing effect occurs, thedistance, or the offset, between the longitudinal axis and the radialcan advantageously be greater than or equal to half of the internaldiameter of the housing of the conveyor or of the screw.

It can moreover be advantageous for these purposes to set the distance,or the offset, between the longitudinal axis and the radial to begreater than or equal to 5 or 7%, or still more advantageously greaterthan or equal to 20%, of the radius of the receiver. In the case ofconveyors with a prolonged intake region or with grooved bushing or withextended hopper, it can be advantageous for this distance or the saidoffset to be greater than or equal to the radius of the receiver. Thisis particularly true for cases where the conveyor is attachedtangentially to the receiver or runs tangentially to the cross sectionof the container.

It is advantageous that the outermost flights of the screw do notprotrude into the container.

It is particularly advantageous if the longitudinal axis of the conveyoror of the screw or the longitudinal axis of the screw closest to theintake aperture runs tangentially with respect to the inner side of theside wall of the container, or the inner wall of the housing does so, orthe enveloping end of the screw does so, where it is preferable thatthere is a drive connected to the end of the screw, and that the screwprovides conveying, at its opposite end, to a discharge aperture whichis in particular an extruder head and which is arranged at the end ofthe housing.

In the case of conveyors that are radially offset, but not arrangedtangentially, it is advantageous to provide that the imaginarycontinuation of the longitudinal axis of the conveyor in a directionopposite to the direction of conveying, at least in sections, passes, inthe form of a secant, through the space within the receiver.

It is advantageous to provide that there is immediate and directconnection between the aperture and the intake aperture, withoutsubstantial separation or a transfer section, e.g. a conveying screw.This permits effective and non-aggressive transfer of material.

The reversal of the direction of rotation of the mixing and comminutionimplements circulating in the container can certainly not result fromarbitrary action or negligence, and it is not possible—either in theknown apparatuses or in the apparatus according to the invention—simplyto allow the mixing implements to rotate in the opposite direction, inparticular because the arrangement of the mixing and comminutionimplements is in a certain way asymmetrical or direction-oriented, andtheir action is therefore only single-sided or unidirectional. If thistype of equipment were to be rotated intentionally in the wrongdirection, a good mixing vortex would not form, and there would be noadequate comminution or heating of the material. Each cutter compactortherefore has its unalterably prescribed direction of rotation of themixing and comminution implements.

In this connection, it is particularly advantageous to provide that themanner of formation, set-up, curvature and/or arrangement of the frontalregions or frontal edges that are associated with the mixing and/orcomminution implements, act on the plastics material and point in thedirection of rotation or of movement, differs when comparison is madewith the regions that, in the direction of rotation or of movement, areat the rear or behind.

An advantageous arrangement here provides that, on the mixing and/orcomminution implement, implements and/or blades have been arrangedwhich, in the direction of rotation or of movement, have a heating,comminuting and/or cutting effect on the plastics material. Theimplements and/or blades can either be fastened directly on the shaft orpreferably be arranged on a rotatable implement carrier or,respectively, a carrier disc arranged in particular parallel to thebasal surface, or be formed therein or moulded onto the same, optionallyas a single piece.

In principle, the effects mentioned are relevant not only to compressingextruders or agglomerators but also to conveying screws that have no, orless, compressing effect. Here again, local overfeed is avoided.

In another particularly advantageous embodiment, it is provided that thereceiver is substantially cylindrical with a level basal surface andwith, orientated vertically in relation thereto, a side wall which hasthe shape of the jacket of a cylinder. In another simple design, theaxis of rotation coincides with the central axis of the receiver. Inanother advantageous formation, the axis of rotation or the central axisof the container have been orientated vertically and/or normally inrelation to the basal surface. These particular geometries optimizeintake performance, with an apparatus design that provides stability andsimple construction.

In this connection it is also advantageous to provide that the mixingand/or comminution implement or, if a plurality of mutually superposedmixing and/or comminution implements have been provided, the lowestmixing and/or comminution implement closest to the base is arranged at asmall distance from the basal surface, in particular in the region ofthe lowest quarter of the height of the receiver, and also that theaperture is similarly arranged. The distance here is defined andmeasured from the lowest edge of the aperture or of the intake apertureto the container base in the edge region of the container. There ismostly some rounding of the edge at the corner, and the distance istherefore measured from the lowest edge of the aperture along theimaginary continuations of the side wall downwards to the imaginaryoutward continuation of the container base. Distances with goodsuitability are from 10 to 400 mm.

In another advantageous embodiment of the treatment process, theradially outermost edges of the mixing and/or comminution implementsalmost reach the side wall.

In a particularly advantageous embodiment, in this connection, thedistance A of the radially outermost point of the lowest mixing and/orcomminution implement, or the distance A of the circle described by thispoint, from the inner surface of the side wall of the container, isgreater than or equal to 20 mm, in particular from ≧20 mm to 60 mm. Thisgives particularly effective and non-aggressive intake behaviour.

The container does not necessarily have to have a cylindrical shape withcircular cross section, even though this shape is advantageous forpractical reasons and reasons of manufacturing technology. Whencontainer shapes that deviate from the cylindrical shape with circularcross section, examples being containers having the shape of a truncatedcone or cylindrical containers which, in plan view, are elliptical oroval, a calculation is required for conversion to a cylindricalcontainer which has circular cross section and the same volume capacity,on the assumption that the height of this imaginary container is thesame as its diameter. Container heights here which are substantiallyhigher than the resultant mixing vortex (after taking into account thedistance required for safety) are ignored, since this excess containerheight is not utilized and it therefore has no further effect on theprocessing of the material.

The expression conveyor means mainly systems with screws that havenon-compressing or decompressing effect, i.e. screws which have purelyconveying effect, but also systems with screws that have compressingeffect, i.e. extruder screws with agglomerating or plastifying effect.

The expressions extruder and extruder screw in the present text meanextruders or screws used for complete or partial melting of thematerial, and also extruders used to agglomerate, but not melt, thesoftened material. Screws with agglomerating effect subject the materialto severe compression and shear only for a short time, but do notplastify the material. The outgoing end of the agglomerating screwtherefore delivers material which has not been completely melted butwhich instead is composed of particles incipiently melted only at theirsurface, which have been caked together as if by sintering. However, inboth cases the screw exerts pressure on the material and compacts thesame.

All of the examples described in the figure below depict conveyors witha single screw, for example single-screw extruders. However, it is alsopossible as an alternative to provide conveyors with more than onescrew, for example twin- or multiscrew conveyors or twin- or multiscrewextruders, in particular with a plurality of identical screws, which atleast have the same diameters d.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention are apparent from thedescription of the inventive examples below of the subject matter of theinvention, which are not to be interpreted as restricting, and which thedrawings depict diagrammatically and not to scale:

FIG. 1 shows a vertical section through an apparatus according to theinvention with extruder attached approximately tangentially.

FIG. 2 shows a horizontal section through the embodiment of FIG. 1.

FIG. 3 shows another embodiment with minimal offset.

FIG. 4 shows another embodiment with relatively large offset.

FIGS. 5 and 6 show a container with deflectors.

FIG. 7 shows a detail.

FIGS. 8 to 10 are diagrams of the arrangement and design of deflectors.

For reasons of clarity, FIGS. 1, 3 and 4 provide only an indication ofthe deflectors.

Neither the containers, nor the screws nor the mixing implements are toscale, either themselves or in relation to one another, in the drawings.By way of example, therefore, the containers are in reality mostlylarger, or the screws longer, than depicted here.

DETAILED DESCRIPTION

The advantageous cutter-compactor/extruder combination depicted in FIG.1 and FIG. 2 for the treatment or recycling of plastics material has acylindrical container or cutter compactor or shredder 1 with circularcross section, with a level, horizontal basal surface 2 and with avertical side wall 9 oriented normally thereto with the shape of acylinder jacket.

Arranged at a small distance from the basal surface 2, at most at about10 to 20%, or optionally less, of the height of the side wall 9—measuredfrom the basal surface 2 to the uppermost edge of the side wall 9—is animplement carrier 13 or a level carrier disc orientated parallel to thebasal surface 2, which carrier or disc can be rotated, in the direction12 of rotation or of movement indicated by an arrow 12, around a centralaxis 10 of rotation, which is simultaneously the central axis of thecontainer 1. A motor 21, located below the container 1, drives thecarrier disc 13. On the upper side of the carrier disc 13, blades orimplements, e.g. cutter blades, 14 have been arranged, and together withthe carrier disc 13 form the mixing and/or comminution implement 3.

As indicated in the diagram, the blades 14 are not arrangedsymmetrically on the carrier disc 13, but instead have a particularmanner of formation, set-up or arrangement on their frontal edges 22facing in the direction 12 of rotation or of movement, so that they canhave a specific mechanical effect on the plastics material. The radiallyoutermost edges of the mixing and comminution implements 3 reach a pointwhich is relatively close to, about 5% of the radius 11 of the container1 from, the inner surface of the side wall 9.

The container 1 has, near the top, a charging aperture through which theproduct to be processed, e.g. portions of plastics foils, is charged byway of example by means of a conveying device in the direction of thearrow. The container 1 can, as an alternative, be a closed container andcapable of evacuation at least as far as an industrial vacuum, thematerial being introduced by way of a system of valves. The said productis received by the circulating mixing and/or comminution implements 3and is raised to form a mixing vortex 30, where the product rises alongthe vertical side wall 9 and, approximately in the region of theeffective container height H, falls back again inward and downward intothe region of the centre of the container, under gravity. The effectiveheight H of the container 1 is approximately the same as its internaldiameter D. In the container 1, a mixing vortex 30 is thus formed, inwhich the material is circulated in a vortex both from top to bottom andalso in the direction 12 of rotation. By virtue of this particulararrangement of the mixing and comminution elements 3 or the blades 14,this type of apparatus can therefore be operated only with theprescribed direction 12 of rotation or movement, and the direction 12 ofrotation cannot be reversed readily or without additional changes.

The circulating mixing and comminution implements 3 comminute and mixthe plastics material introduced, and thereby heat and soften it by wayof the mechanical frictional energy introduced, but do not melt it.After a certain residence time in the container 1, the homogenized,softened, doughy but not molten material is, as described in detailbelow, removed from the container 1 through an aperture 8, passed intothe intake region of an extruder 5, and received by a screw 6 there andsubsequently melted.

At the level of the, in the present case single, comminution and mixingimplement 3, the said aperture 8 is formed in the side wall 9 of thecontainer 1, and the pretreated plastics material can be removed fromthe interior of the container 1 through this aperture. The material ispassed to a single-screw extruder 5 arranged tangentially on thecontainer 1, where the housing 16 of the extruder 5 has, situated in itsjacket wall, an intake aperture 80 for the material to be received bythe screw 6. This type of embodiment has the advantage that the screw 6can be driven from the lower end in the drawing by a drive, depictedonly diagrammatically, in such a way that the upper end of the screw 6in the drawing can be kept free from the drive. The discharge aperturefor the plastified or agglomerated plastics material conveyed by thescrew 6 can therefore be arranged at this upper end, e.g. in the form ofan extruder head not depicted. The plastics material can therefore beconveyed without deflection by the screw 6 through the dischargeaperture; this is not readily possible in the embodiments according toFIGS. 3 and 4.

There is connection for conveying of material or for transfer ofmaterial between the intake aperture 80 and the aperture 8, and in thepresent case this connection to the aperture 8 is direct and immediateand involves no prolonged intervening section and no separation. Allthat is provided is a very short transfer region.

In the housing 16, there is a screw 6 with compressing effect, mountedrotatably around its longitudinal axis 15. The longitudinal axis 15 ofthe screw 6 and that of the extruder 5 coincide. The extruder 5 conveysthe material in the direction of the arrow 17. The extruder 5 is aconventional extruder known per se in which the softened plasticsmaterial is compressed and thus melted, and the melt is then dischargedat the opposite end, at the extruder head.

The mixing and/or comminution implements 3 or the blades 14 are atapproximately the same level as the central longitudinal axis 15 of theextruder 5. The outermost ends of the blades 14 have adequate separationfrom the flights of the screw 6.

In the embodiment according to FIGS. 1 and 2, the extruder 5 is, asmentioned, attached tangentially to the container 1, or runstangentially in relation to its cross section. In the drawing, theimaginary continuation of the central longitudinal axis 15 of theextruder 5 or of the screw 6 in a direction opposite to the direction 17of conveying of the extruder 5 towards the rear passes the axis 10 ofrotation and does not intersect the same. On the outflow side, there isan offset distance 18 between the longitudinal axis 15 of the extruder 5or of the screw 6 and the radius 11 that is associated with thecontainer 1 and that is parallel to the longitudinal axis 15 and thatproceeds outwards from the axis 10 of rotation of the mixing and/orcomminution implement 3 in the direction 17 of conveyance of theconveyor 5. In the present case, the imaginary continuation of thelongitudinal axis 15 of the extruder 5 towards the rear does not passthrough the space within the container 1, but instead passes the same ata short distance therefrom.

The distance 18 is somewhat greater than the radius of the container 1.There is therefore a slight outward offset of the extruder 5, or theintake region is somewhat deeper.

The expressions “opposite”, “counter-” and “in an opposite sense” heremean any orientation of the vectors with respect to one another which isnot acute-angled, as explained in detail below.

In other words, the scalar product of a direction vector 19 which isassociated with the direction 12 of rotation and the orientation ofwhich is tangential to the circle described by the outermost point ofthe mixing and/or comminution implement 3 or tangential to the plasticsmaterial passing the aperture 8, and which points in the direction 12 ofrotation or movement of the mixing and/or comminution implements 3, andof a direction vector 17 which is associated with the direction ofconveying of the extruder 5 and which proceeds in the direction ofconveying parallel to the central longitudinal axis 15 is everywherezero or negative, at each individual point of the aperture 8 or in theregion radially immediately prior to the aperture 8, and is nowherepositive.

In the case of the intake aperture in FIGS. 1 and 2, the scalar productof the direction vector 19 for the direction 12 of rotation and of thedirection vector 17 for the direction of conveying is negative at everypoint of the aperture 8.

The angle α between the direction vector 17 for the direction ofconveying and the direction vector for the direction 19 of rotation,measured at the point 20 that is associated with the aperture 8 andsituated furthest upstream in relation to the direction 12 of rotation,or at the edge associated with the aperture 8 and situated furthestupstream, is approximately maximally about 170°.

As one continues to proceed downwards along the aperture 8 in FIG. 2,i.e. in the direction 12 of rotation, the oblique angle between the twodirection vectors continues to increase. In the centre of the aperture8, the angle between the direction vectors is about 180° and the scalarproduct is maximally negative, and further downwards from there theangle indeed becomes >180° and the scalar product in turn decreases, butstill remains negative. However, these angles are no longer termedangles α, since they are not measured at point 20.

An angle β, not included in the drawing in FIG. 2, measured in thecentre of the aperture 8, between the direction vector for the direction19 of rotation and the direction vector for the direction 17 ofconveying is about 178° to 180°.

The apparatus according to FIG. 2 represents the first limiting case orextreme value. This type of arrangement can provide a verynon-aggressive stuffing effect or a particularly advantageous feed, andthis type of apparatus is particularly advantageous for sensitivematerials which are treated in the vicinity of the melting range, or forproduct in the form of long strips.

FIG. 3 shows an alternative embodiment in which the extruder 5 is notattached tangentially to the container 1 but instead is attached by itsend 7. The screw 6 and the housing 16 of the extruder 5 have beenadapted in the region of the aperture 8 to the shape of the inner wallof the container 1, and have been offset backwards so as to be flush. Nopart of the extruder 5 protrudes through the aperture 8 into the spacewithin the container 1.

The distance 18 here corresponds to about 5 to 10% of the radius 11 ofthe container 1 and to about half of the internal diameter d of thehousing 16. This embodiment therefore represents the second limitingcase or extreme value with the smallest possible offset or distance 18,where the direction 12 of rotation or of movement of the mixing and/orcomminution implements 3 is at least slightly opposite to the direction17 of conveying of the extruder 5, and specifically across the entirearea of the aperture 8.

The scalar product in FIG. 3 at that threshold point 20 situatedfurthest upstream is precisely zero, where this is the point located atthe edge 20′ that is associated with the aperture 8 and situatedfurthest upstream. The angle α between the direction vector 17 for thedirection of conveying and the direction vector for the direction 19 ofrotation, measured at point 20 in FIG. 3, is precisely 90°. If oneproceeds further downwards along the aperture 8, i.e. in the direction12 of rotation, the angle between the direction vectors becomes evergreater and becomes an oblique angle >90°, and at the same time thescalar product becomes negative. However, at no point, or in no regionof the aperture 8 is the scalar product positive, or the angle smallerthan 90°. No local overfeed can therefore occur even in a subregion ofthe aperture 8, and no detrimental excessive stuffing effect can occurin a region of the aperture 8.

This also represents a decisive difference in relation to a purelyradial arrangement, since there would be an angle α<90° at point 20 orat the edge 20′ in a fully radial arrangement of the extruder 5, andthose regions of the aperture 8 situated, in the drawing, above theradial 11 or upstream thereof or on the inflow side thereof would have apositive scalar product. It would thus be possible for locally meltedplastics product to accumulate in these regions.

FIG. 4 depicts another alternative embodiment in which the extruder 5 issomewhat further offset than in FIG. 3 on the outflow side, but stillnot tangentially as in FIGS. 1 and 2. In the present case, as also inFIG. 3, the rearward imaginary continuation of the longitudinal axis 15of the extruder 5 passes through the space within the container 1 in themanner of a secant. As a consequence of this, the aperture 8 is—measuredin the circumferential direction of the container 1—wider than in theembodiment according to FIG. 3. The distance 18 is also correspondinglygreater than in FIG. 3, but somewhat smaller than the radius 11. Theangle α measured at point 20 is about 150°, and the stuffing effect istherefore reduced in comparison with the apparatus of FIG. 3; this ismore advantageous for certain sensitive polymers. The inner wall of thehousing 16 or the right-hand-side inner edge, as seen from the container1, is tangential to the container 1, and therefore, unlike in FIG. 3,there is no oblique transitional edge. At this point that is associatedwith the aperture 8 and is furthest downstream, on the extreme left-handside in FIG. 4, the angle is about 180°.

In order, in all these container-extruder combinations, to achieve idealconditions in respect of the residence times of the plastic for theprecomminution process, the predrying process and the preheating processfor the plastics material in the container 1, the diameter D of thecontainer 1 has the following relationship to the external diameter d ofthe screw 6: D=10.

${D = {10 \cdot \sqrt[3]{K \cdot d^{2}}}},$where D is the internal diameter in millimetres of the container 1, d isthe diameter in millimetres of the screw 6 and K is a constant, thisconstant being in the range from 60 to 180.

As mentioned in the introduction, the specific ratio between theinternal diameter D of the container 1 and the average diameter d of thescrew 6 ensures that, with a relatively low average residence time ofthe material, product of adequately constant thermal and mechanicalnature is always passed into the intake aperture 80 of the housing 16,even when the product to be processed is difficult for this type ofprocessing, an example being foil residues of differing nature(thickness, size, etc.). The mixing or comminution implements 3 provide,by virtue of their particular direction 12 of rotation relative to thedirection of conveying of the screw 6, non-aggressive intake of thematerial into the extruder 5, and ensure that it is possible to achievea homogeneous melt at high throughput. The deflectors 50 provided assistthe implements 3. The selected direction 12 of rotation of the mixing orcomminution implements 3 acts synergistically with the addition of thedeflectors 50. Deflectors 50 of this type are attached on the internalwall of the container 1, for example attached by welding. The deflectors50 have a prescribed length l, and also a prescribed width b, which canbe adapted to be appropriate to the respective conditions. In principle,the deflectors 50 can also be attached exchangeably on the internal wallof the container. The number of the deflectors 50 arranged along theinternal wall of the container 1 is adapted to be appropriate to theintended use of the apparatus.

FIG. 5 is a diagram of a section through a container 1 in which thereare two deflectors 50 arranged on opposite regions of internal wall. Oneof the deflectors 50 is opposite to the intake aperture 80; the otherdeflector, which has an extension 57 at its end, has a lower end regionor a lower end 58 which is above the intake aperture 80. At 70, asurrounding area, or a region around the intake aperture 80, isdepicted, within which the end or the lowest point 58 of at least one ofthe stripping elements 50 provided should preferably be been arranged.

FIG. 6 is a plan view of the container depicted in FIG. 5. The twodeflectors 50 are seen, arranged on mutually opposite internal wallareas.

FIG. 7 shows a detailed section of the connection of a conveyor screw orextruder screw 6 to the container 1. Above the intake aperture 80 thereis a deflector 50. This bar-shaped deflector 50 is secured by its narrowside on the container wall, and protrudes into the interior of thecontainer.

The deflector 50 has a height profile, where the height level decreasesin the direction 12 of rotation of the mixing implement 3, seen fromabove, as can be seen from FIGS. 8 and 9. The angle included by eachdeflector 50 here, at least over most of its length, with a plane E isan acute angle α, where this plane E is perpendicular to the axis 10 ofrotation of the rotating mixing and comminution implements 3.

The deflector 50 can extend with constant angle α in the form of astraight bar along the internal wall of the container. It isself-evident that the deflectors 50 follow the internal wall of thecontainer and, in plan view, as depicted in FIG. 6, have an appropriatecurvature along the circumference of the container. However, the angle αis measured in relation to the plane E, and in the event that adeflector 50 has a curved height profile, the respective tangentialangle at the points under consideration on the deflector 50 can be takenas angle α.

It is advantageous if, as depicted in the figures, at least over asubsection of the deflector 50, the angle α is from 15° to 45°,preferably from 20° to 40°.

From FIGS. 8 and 9, it can be seen that the height profile of thedeflector 50 mostly exhibits a convex curvature directed against thedirection 12 of rotation of the implements 3. However, the drawing ofFIG. 8 also includes a deflector 50A which has a convex curvaturedirected in the direction 12 of rotation of the implements 3.

FIG. 8 shows a large number of deflectors 50 having different lengthand/or different height profile. From FIG. 8 it can also be seen thatthe direction 12 of rotation of the implements 3 is opposite to thedirection FS of conveying of the screw 6, as has been explained indetail with reference to FIGS. 1 to 4. The region 70 surrounding theintake aperture 80 can be seen in FIG. 8. It is advantageous that thelower end region or the lower end 58 of one or more deflectors 50 iswithin this region 79.

The lower end of the deflector 50 is within a circumferential region ofthe container wall between the two lateral edges 55, 56 of the intakeaperture 80, and this region is optionally enlarged in the direction ofrotation of the implements 3 only by at most from 50% to 80% of thelength of a longitudinal edge 52, 53.

The lower end of the deflector 50 is moreover at a level that is withinthe region 70 between the upper and lower longitudinal edge 52, 53 ofthe intake aperture 80 and optionally at most from 50% to 80% of theheight HE of the intake aperture 80 above the upper longitudinal edge 52or at most from 20% to 30% of the height HE of the intake aperture 80below the lower edge 53 of the intake aperture 80.

In relation to the upper ends of the deflectors, it is possible that,viewed in the direction 12 of rotation of the mixing implements 3, theupper end of the deflector 50 is at least 10° to 15°, preferably 30° to55°, prior to that edge 56 that is associated with the intake aperture80 and that is situated upstream in the direction of rotation, or afterthat edge 55 that is associated with the intake aperture 80 and that issituated downstream in the direction of rotation. This positioning ofthe deflectors 50 considerably improves intake performance.

As can be seen from FIG. 10, the width b and the length l of thedeflectors 50 can be adapted and prescribed to be appropriate to theprevailing conditions. FIG. 10 depicts a deflector 50 with rectangularlongitudinal cross section. Alongside this on the right-hand side, thedeflector 50 depicted widens in the direction towards its lower end 58,in its final section. The width b of the deflector depicted on theright-hand side differs over its length l, or the deflector has beenbevelled in its end region.

It is also possible that a plurality of deflectors 50 end in the regionof the intake aperture 80. It is preferable that the ends 58 of thedeflectors 50 are within a circumferential region 70 that is downstreamin the direction of rotation in relation to the edge 52, and it ispreferable that they end at the height level of the edge 52 ortherebelow 50B denotes deflectors of this type.

The other deflectors 50 arranged in the container 1 and remote from theintake aperture (80) can have the same features, in particular inrelation to height profile and height level, as the deflectors 50 in thecircumferential region of the intake aperture 80.

The invention claimed is:
 1. An apparatus for the pretreatment andsubsequent conveying, plastification or agglomeration of plastics, witha container (1) for the material to be processed, where, in thecontainer (1), at least one mixing and/or comminution implement (3)which rotates around an axis (10) of rotation and which is intended forthe mixing, heating and optionally comminution of the plastics material,where an aperture (8) through which the pretreated plastics material canbe removed from the interior of the container (1) is formed in a sidewall (9) of the container (1) in the region of the level of the, or of amixing and/or comminution implement (3) that is closest to the aperture(8), where at least one conveyor (5) is provided to receive thepretreated material, and has at least one screw (6) which rotates in ahousing (16) and which has plastifying or agglomerating action, wherethe housing (16) has, located at its end (7) or in its jacket wall, anintake aperture (80) for the material to be received by the screw (6),and there is connection between the intake aperture (80) and theaperture (8), wherein the imaginary continuation of the centrallongitudinal axis (15) of the conveyor (5) or of the screw (6) closestto the intake aperture (80), in a direction opposite to a direction (17)of conveying of the conveyor (5), passes, and does not intersect, theaxis (10) of rotation, where, on the outflow side in a direction (12) ofrotation, there is an offset distance (18) between the longitudinal axis(15) of the conveyor (5) or of the screw (6) closest to the intakeaperture (80), and a radius (11) that is associated with the container(1) and that is parallel to the longitudinal axis (15) and that proceedsoutwards from the axis (10) of rotation of the mixing and/or comminutionimplement (3) in the direction (17) of conveying of the conveyor (5),and wherein, on an internal wall area of the container (1) there is atleast one bar-shaped deflector (50) which is directed into the interiorof the container (1), and the height profile of which decreases in thedirection (12) of rotation of the mixing implement (3), seen from above,and the angle included thereby, over its length, with a plane (E)perpendicular to the axis (10) of rotation of the mixing implement (3)is an acute angle (α), wherein the lower end representing the lowestsection (58) of the deflector (50) is followed by an extension (57),which is directed upwards in the direction (12) of rotation, as a singlepiece.
 2. The apparatus according to claim 1, wherein the acute angle(α) is constant at least in sections over the length of the deflector(50), or that the profile of the deflector (50) is curved downwards, atleast over a section of its length (l), and in that case the acute angle(α) represents the tangential angle present at the respective point onthe deflector (50).
 3. The apparatus according to claim 1, wherein theacute angle (α) in the central region of the deflector (50), is from 15°to 45°.
 4. The apparatus according to claim 1, wherein the acute angle(α) decreases towards the lower end of the deflector (50), optionally toan angle α=0°.
 5. The apparatus according to claim 1, wherein the lowerend (58) of the deflector (50) is within a circumference (70) betweenthe two lateral edges (55, 56) of the intake aperture (80), and thisregion is optionally enlarged in the direction of rotation of theimplements (3) only by at most from 50% to 80% of the length of alongitudinal edge (52, 53).
 6. The apparatus according to claim 1,wherein the lower end (58) of the deflector (50) is at a height level onthe container wall, where this level is within the region (70) betweenthe upper and lower longitudinal edge (52, 53) of the intake aperture(80) and optionally at most from 50% to 80% of the height (HE) of theintake aperture (80) above the upper longitudinal edge (52) or at mostfrom 20% to 30% of the height (HE) of the intake aperture (80) below thelower edge (53) of the intake aperture (80).
 7. The apparatus accordingto claim 1, wherein the deflector (50) protrudes radially from theinternal wall of the container.
 8. The apparatus according to claim 1,wherein the bar-shaped deflector (50) has a rectangular cross sectionoptionally rounded at the edges projecting into the container (1), andis secured by its narrow side on the internal wall of the container (1).9. The apparatus according to claim 1, wherein the width of thedeflector (50) optionally decreases in stages in the direction towardsthe end, or that the deflector (50) is widened in the end region. 10.The apparatus according to claim 1, wherein, viewed in the direction(12) of rotation of the mixing implements (3), the upper end of thedeflector (50) is at least 10° to 15°, prior to that edge (56) that isassociated with the intake aperture (80) and that is situated upstreamin the direction of rotation, or after that edge (55) that is associatedwith the intake aperture (80) and that is situated downstream in thedirection of rotation.
 11. The apparatus according to claim 1, whereinthe width (b) of the deflector (50) is in the range from 1% to 10% ofthe diameter of the container, and/or that the width of the deflector(50) is greater than 15 mm.
 12. The apparatus according to claim 1,wherein the deflector (50) ends outside of the open cross section of theintake aperture (80).
 13. The apparatus according to claim 1, wherein,for a conveyor (5) in contact with the container (1), the scalar productof a direction vector describing the portion of the mixing and/orcomminution implement (3) nearest the aperture when the mixing and/orcomminution implement (3) is adjacent the aperture, and anotherdirection vector describing the conveying of the conveyor (5) is zero ornegative.
 14. The apparatus according to claim 1, wherein an angle (β)between a direction vector describing the motion of the portion of themixing and/or comminution implement (3) nearest the aperture when themixing and/or comminution implement (3) is adjacent the aperture, andanother direction vector describing the direction of the conveying ofthe conveyor (5) is greater than or equal to 90° and less than or equalto 180°.
 15. The apparatus according to claim 1, wherein an angle (β)between a direction vector describing the motion of the portion of themixing and/or comminution implement (3) nearest the aperture when themixing and/or comminution implement (3) is adjacent the aperture, andanother direction vector describing the direction of the conveying ofthe conveyor (5) is from 170° to 180°.
 16. The apparatus according toclaim 1, wherein the offset distance (18) is greater than or equal tohalf of the internal diameter of the housing (16) of the conveyor (5) orof the screw (6), and/or greater than or equal to 7%, of the radius ofthe container (1), or wherein the distance (18) is greater than or equalto the radius of the container (1).
 17. The apparatus according to claim1, wherein the imaginary continuation of the longitudinal axis (15) ofthe conveyor (5) in a direction opposite to the direction of conveyingis arranged in the manner of a secant in relation to the cross sectionof the container (1), and, at least in sections, passes through thespace within the container (1).
 18. The apparatus according to claim 1,wherein the conveyor (5) is attached tangentially to the container (1)or runs tangentially in relation to the cross section of the container(1), or wherein the longitudinal axis (15) of the conveyor (5) or of thescrew (6) or the longitudinal axis of the screw (6) closest to theintake aperture (80) runs tangentially with respect to the inner side ofthe side wall (9) of the container (1), or the inner wall of the housing(16) does so, or the enveloping end of the screw (6) does so, wherethere is a drive connected to the end (7) of the screw (6), and that thescrew provides conveying, at its opposite end, to a discharge aperturewhich is an extruder head and which is arranged at the end of thehousing (16).
 19. The apparatus according to claim 1, wherein there isimmediate and direct connection between the aperture (8) and the intakeaperture (80), without substantial separation, and without transfersection or conveying screw.
 20. The apparatus according to claim 1,wherein the mixing and/or comminution implement (3) comprises implementsand/or blades (14) which, in the direction (12) of rotation or ofmovement, have a comminuting, cutting and heating effect on the plasticsmaterial, where the implements and/or blades (14) are arranged or formedon or at a rotatable implement carrier and which is arranged parallel toa basal surface (12).
 21. The apparatus according to claim 1, whereinfrontal edges (22) that are associated with blades (14) of the mixingand/or comminution implement (3) act on the plastics material and pointin the direction (12) of rotation or of movement, differs whencomparison is made with the regions that, in the direction (12) ofrotation or of movement, the rearward regions or rearward edges (22) ofthe mixing and/or comminution implement (3) or the blades (14).
 22. Theapparatus according to claim 1, wherein the container (1) issubstantially cylindrical with circular cross section and with a levelbasal surface (2) and with, orientated vertically in relation thereto, aside wall (9) which has the shape of the jacket of a cylinder, and/orthe axis (10) of rotation of the mixing and/or comminution implement (3)coincides with the central axis of the container (1), and/or the axis(12) of rotation or the central axis are orientated vertically and/ornormally in relation to the basal surface (2).
 23. The apparatusaccording to claim 1, wherein a lowest implement carrier (13) or alowest of the mixing and/or comminution implement (3) and/or theaperture (8) are arranged in the lowest quarter of the height of thecontainer (1), at a distance of from 10 mm to 400 mm from a basalsurface (2).